The present invention relates to contactless electronic tags, produced by means of a contactless integrated circuit and a coil antenna.
In recent years, so-called xe2x80x9ccontactlessxe2x80x9d integrated circuits have been developed and devised, that are capable of receiving or transmitting data by inductive coupling, through a coil antenna. Examples of embodiments of these integrated circuits are described in applications WO 98/02840, WO 98/02980, WO 98/05123, WO 98/06057 and WO 98/06056 in the name of the applicant. Furthermore, these integrated circuits are being standardized and are more particularly the subject of the draft standard ISO 14443, mentioned herein without restriction.
These contactless integrated circuits have the advantage of being able to be electrically powered by electromagnetic induction through their coil antenna, without it being necessary to attach a voltage source such as an electric cell to them. On the other hand, they offer quite short communication distances, in the order of a few centimetres to some tens of centimetres, and are intended for so-called proximity applications. Among these applications, the most common ones are the production of smart cards, electronic badges and electronic tags.
Contactless electronic tags can themselves be used in various applications such as the identification of products or goods, inventory management and freight forwarding management. In these applications, the electronic tags are generally placed on containers, packing boxes or trays for the transportation of goods such as pallets. As an example, FIG. 1 represents an electronic tag 1 placed on a pallet 2 for the transportation of goods. The electronic tag 1 comprises a contactless integrated circuit 10 and a coil antenna Ls connected to the integrated circuit 10, the assembly being arranged on a support 11, such as a self-adhesive plastic sheet fixed onto the pallet 2 for example. When the integrated circuit 10 is activated by a magnetic field FLD sent by the coil Lp of a tag reader RDT, data can be exchanged between the reader RDT and the integrated circuit 10, by inductive coupling. The integrated circuit 10 generally comprises a read and write access electrically erasable and programmable memory, so that the electronic tag 1 can be used to store data identifying the pallet, its age, the date it was put into service, as well as the goods it carries, in particular the type, the manufacturing date, the origin and the destination of the goods, etc.
In this application, it is desirable to be able to read the electronic tag automatically upon transportation of the pallet, such as when the latter is picked up by a pallet jack (forklift truck) for example. The electronic tag 1 is therefore arranged on one side of the pallet 2, as shown in FIG. 1, and a reader RDT is integrated into the front of the pallet jack (not represented), facing the pallet-carrier fork.
The disadvantage of this solution is that due to the short communication distance offered by the inductive coupling technique, the side of the pallet 2 that bears the electronic tag 1 must be facing the front of the pallet jack so that the coil Lp of reader RDT is located in the proximity of the coil Ls of the tag 1.
However, in practice, the pallets are likely to be picked up on several of their sides, at least by two of their sides for certain types of pallets and by any one side for other types of pallets. For example, the pallets may be picked up by one side when they are deposited in a storage site, and then be picked up by their opposite side when they are removed. A similar problem occurs for the handling of objects such as boxes or containers of goods, when an automatic reading of electronic tags placed on one face of these objects is required.
Thus, the purpose of the present invention is to provide a means enabling an electronic tag placed on one face of a three-dimensional object to be read from a different face of the object to the one on which the electronic tag is placed.
This object is achieved by providing an electronic tag comprising at least one contactless integrated circuit and at least one main coil antenna, in which the main coil antenna comprises at least two non-coplanar and/or non-coaxial windings arranged in series, the two windings, if they are coaxial, being a distance apart from each other which is at least equal to the diameter of one of the windings.
According to one embodiment, the integrated circuit is connected to the two terminals of the main coil antenna.
According to one embodiment, the main coil antenna is in closed loop and the integrated circuit is connected to an auxiliary coil which is inductively coupled to one of the windings of the main coil antenna in closed loop.
According to one embodiment, each of the windings of the main coil antenna is arranged on one face of a three-dimensional object.
The present invention also relates to a three-dimensional object comprising two non-coplanar and/or non-coaxial windings arranged in series at least on two of its faces or in the vicinity of two of its faces, forming together a coil antenna for electronic tag, the two windings, if they are coaxial, being a distance apart from each other which is at least equal to the diameter of one of the windings.
The present invention also relates to a three-dimensional object comprising two non-coaxial windings arranged in series on one of its faces, forming together a coil antenna for electronic tag.
According to one embodiment, the object comprises an integrated circuit on one of its faces, or i n the vicinity of one of its faces, said integrated circuit being connected to the two terminals of the coil antenna.
According to one embodiment, the object comprises an integrated circuit on one of its faces, or in the vicinity of one of its faces, said integrated circuit being connected to a first auxiliary coil which is inductively coupled to one of the windings of the coil antenna.
According to one embodiment, the object comprises at least a second integrated circuit connected to a second auxiliary coil which is inductively coupled to one of the windings of the coil antenna.
According to one embodiment, the coil antenna is incorporated into the body of the object.
According to one embodiment, the object forms a pallet for the transportation of goods.
According to one embodiment, the object forms a cardboard box for the transportation of goods.